Current climate: April 2017

11 May 2017

April 2017 was characterised by higher than normal atmospheric pressure to the south and southeast of the South Island, along with lower than normal atmospheric pressure over and to the north of the North Island. This pressure pattern resulted in more northeasterly wind flow than normal, bringing with it moist tropical air masses and record-high rainfall for parts of the North Island.

Rainfall

Prolific rainfall totals were observed across nearly the entire North Island, with more than twice the normal April rainfall (>200%) recorded in the large majority of locations. Amounts exceeding three times the April normal (>300%) were also observed in several places. In the North Island, only northern and western Northland received near normal rainfall (80-119% of normal). The northern and eastern South Island also received widespread rainfall in excess of 200% of the April normal, with a couple of locations picking up more than 300% of normal April rainfall. Conversely, much of the West Coast saw near normal (80-119% of normal) to above normal (120-149% of normal) rainfall. Meanwhile, much of Southland and Queenstown-Lakes received below normal rainfall (50-79% of April normal).

Temperature

The majority of the North Island experienced well above average (>1.20°C above average) or above average (0.51 to 1.20°C above average) temperatures in April. Isolated locations in the central and southern North Island, as well as the northern and eastern South Island, recorded near average (-0.50 to 0.50°C of average) temperatures. Temperatures were primarily well above average (>1.20°C above average) or above average (0.51 to 1.20°C above average) in the western and southern South Island.

Sunshine

Near normal (90-109% of normal) to below normal (75-89% of normal) sunshine hours were recorded for most locations around New Zealand, while isolated areas of well below normal (<75% of normal) sunshine were observed in the lower North Island and in Central Otago. Isolated above normal (110-125% of normal) sunshine was recorded in the western North Island.

Soil Moisture

As of 1 May 2017, soils across most of the North Island were much wetter than normal for the time of year. In the South Island, soils were much wetter than normal in most of the north and east. However, much drier than normal soils were located across Queenstown-Lakes District and much of Southland.

Departure from average air temperature for April 2017.

End of month water balance in the pasture root zone for an average soil type where the available water capacity is taken to be 150 mm.